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Mazzotta C, Stojanovic A, Romano V, Addabbo G, Borroni D, Balamoun AA, Ferrise M. Ray-Tracing Transepithelial Excimer Laser Central Corneal Remodeling Plus Pachymetry-Guided Accelerated Corneal Crosslinking for Keratoconus. Cornea 2024; 43:285-294. [PMID: 37699556 PMCID: PMC10836791 DOI: 10.1097/ico.0000000000003380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 08/02/2023] [Accepted: 08/05/2023] [Indexed: 09/14/2023]
Abstract
PURPOSE The aim of this study was to report the 12 to 96 months results of a tissue-preservation algorithm based on ray-tracing-guided transepithelial excimer laser central corneal ablation (RT t-PRK) combined with individualized pachymetry-guided accelerated crosslinking (M nomogram ACXL) in young adult patients with stable keratoconus (KC). METHODS This was a prospective interventional study including 38 eyes of 38 young adult patients (stage II KC) with a mean age of 35 years (range 26-46 years) who underwent simultaneous RT with t-PRK plus pachymetry-based ACXL in the worst eye. The treatments were performed using the iViS Suite iRES Excimer Laser (Ligi, Taranto, Italy). Ray-tracing-guided treatments were planned using the customized interactive programmed transepithelial ablation (CIPTA) 2 web software and diagnostic data were assessed by the Precisio 2 tomographer (Ligi, Taranto, Italy) and Sirius tomographer (C.S.O., Florence, Italy). The main outcome measures included uncorrected distance visual acuity, best spectacle-corrected visual acuity, Kmax, high-order aberrations, minimum corneal thickness, and posterior elevation, with a mean follow-up of 52 months (range 12-96 m). RESULTS The mean UDVA improved + 3.5 ±1.28 Snellen lines (SL); 38% gained ≥ 4 ±1.34 SLs, 35% ≥ 3 ±1.21 SLs, 22% ≥ 2 ±1.12 SLs, and 5% ≥ 1 ±0.75 SLs. The mean best spectacle-corrected visual acuity increased by + 4.3 ±1.3 SL. Sixty-eight percent gained ≥ 4 ±0.88 SLs and 30% ≥ 3 ±0.78 SL. No SLs were lost. CONCLUSIONS RT t-PRK plus ACXL significantly improved the quality of vision in patients with KC, preventing overcorrection and minimizing tissue consumption.
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Affiliation(s)
- Cosimo Mazzotta
- Department of Medicine, Surgery and Neurosciences, Postgraduate Ophthalmology School, Siena University, Italy
- Departmental Ophthalmology Unit, AUSL Toscana Sud Est, Campostaggia, Siena, Italy
- Siena Crosslinking Center, Siena, Italy
| | | | - Vito Romano
- Eye Clinic, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, University of Brescia, Brescia, Italy
- ASST Civil Hospital of Brescia, Brescia, Italy
| | - Giuseppe Addabbo
- Eye Clinic, Hospital “SS. Annunziata”, ASL Taranto, Taranto, Italy
| | - Davide Borroni
- Department of Doctoral Studies, Riga Stradins University, Riga, Latvia
| | - Ashraf Armia Balamoun
- Watany Eye Hospital (WEH), Research and Development Centre, Cairo, Egypt
- Ashraf Armia Eye Clinic, Giza, Egypt; and
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Markuszewski B, Wylęgała A, Szentmáry N, Langenbucher A, Markuszewska A, Wylęgała E. Comparative Analysis of the Visual, Refractive and Aberrometric Outcome with the Use of 2 Intraocular Refractive Segment Multifocal Lenses. J Clin Med 2023; 13:239. [PMID: 38202246 PMCID: PMC10779799 DOI: 10.3390/jcm13010239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/25/2023] [Accepted: 12/27/2023] [Indexed: 01/12/2024] Open
Abstract
To demonstrate the results of ray tracing higher- and lower-order aberrations in pseudophakic eyes with rotationally asymmetrical segment multifocal lenses, total high- and low-order aberrations, measured by root mean square value (RMS), refraction, uncorrected distance and uncorrected near visual acuity (UCDVA and UCNVA), and tear break-up time, were measured at scotopic size in 42 eyes of patients implanted with bifocal refractive Mplus15/Mplus30 IOL with +1.5 dpt near addition (42 eyes of patients implanted with Mplus15)/+3.0 dpt near addition (91 eyes of patients implanted with Mplus30), and 107 eyes of control group. No significant differences were noticed between the examined groups concerning UCDVA, UCNVA, and tear break-up time (p < 0.001). Coma and total high-order aberrations were significantly higher for the Mplus30 lens in comparison to the Mplus15 lens and the control group (Coma, Trefoil p < 0.001, Secondary Astigmatism p = 0.002). The spherical aberrations were significantly higher in the lower-addition lens (p = 0.016) in comparison to the control group and to the higher-addition lens group (p < 0.001). Both intraocular lens models were successful at reaching refractive aim, good distance, and near function with the lower higher-order aberrations for the low-addition lens.
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Affiliation(s)
- Bartłomiej Markuszewski
- Chair and Clinical Department of Ophthalmology, Faculty of Medical Sciences, Zabrze Medical University of Silesia, 40-760 Katowice, Poland; (A.W.)
- Wrocławskie Centrum Okulistyczne, 50-231 Wrocław, Poland
| | - Adam Wylęgała
- Chair and Clinical Department of Ophthalmology, Faculty of Medical Sciences, Zabrze Medical University of Silesia, 40-760 Katowice, Poland; (A.W.)
| | - Nóra Szentmáry
- Dr. Rofl M. Schwiete Center for Limbal Stem Cell and Aniridia Research, Saarland University, 66424 Homburg, Germany;
| | - Achim Langenbucher
- Department of Experimental Ophthalmology, Saarland University, 66424 Homburg, Germany
| | | | - Edward Wylęgała
- Chair and Clinical Department of Ophthalmology, Faculty of Medical Sciences, Zabrze Medical University of Silesia, 40-760 Katowice, Poland; (A.W.)
- Department of Ophthalmology, District Railway Hospital, 40-760 Katowice, Poland
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3
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Yeh CC, Huang TW, Lin YR, Su GD. The Design and Fabrication of Large-Area Under-Screen Fingerprint Sensors with Optimized Aperture and Microlens Structures. Sensors (Basel) 2023; 23:8731. [PMID: 37960431 PMCID: PMC10648296 DOI: 10.3390/s23218731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 10/20/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023]
Abstract
In this paper, we designed and fabricated an optical filter structure applied to the FoD (Fingerprint on Display) technology of the smartphone, which contains the microlens array, black matrix, and photodetector to recognize the fingerprint on a full touchscreen. First, we used optical ray tracing software, ZEMAX, to simulate a smartphone with FoD and a touching finger. We then further discussed how the aperture and microlens influence the fingerprint image in this design. Through numerical analysis and process constraint adjustment to optimize the structural design, we determined that a modulation transfer function (MTF) of 60.8% can be obtained when the thickness of the black matrix is 4 μm, allowing successful manufacturing using photolithography process technology. Finally, we used this filter element to take fingerprint images. After image processing, a clearly visible fingerprint pattern was successfully captured.
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Affiliation(s)
| | | | | | - Guo-Dung Su
- Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan
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4
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Sánchez Iglesias F, Fernández López A. Evaluating Structural Details' Influence on Elastic Wave Propagation for Composite Structures via Ray Tracing. Sensors (Basel) 2023; 23:7220. [PMID: 37631756 PMCID: PMC10459853 DOI: 10.3390/s23167220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 08/10/2023] [Accepted: 08/11/2023] [Indexed: 08/27/2023]
Abstract
This study presents a novel method based on ray tracing for analyzing wave propagation in composites specifically tailored for structural health monitoring applications. This method offers distinct advantages over the commonly used finite element method mainly in computational resource utilization, which has become a limiting factor for these kinds of analyses. The ray tracing method is evaluated against a number of example cases representing structural details such as thickness changes, stringers, or simulated damage, and the significance of ray tracing to study wave propagation under these conditions and how it can serve as a valuable tool for structural health monitoring are highlighted. This model has been developed as part of a complete SHM framework with the intention of being an efficient and simple way to calculate wave propagation and therefore it could be used as a way to determine relevant damage indicators or train an artificial intelligence model.
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Landers D, Clancy I, Weber D, Dunin-Borkowski RE, Stewart A. TEMGYM Basic: transmission electron microscopy simulation software for teaching and training of microscope operation. J Appl Crystallogr 2023; 56:1267-1276. [PMID: 37555218 PMCID: PMC10405588 DOI: 10.1107/s1600576723005174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 06/09/2023] [Indexed: 08/10/2023] Open
Abstract
An interactive simulation of a transmission electron microscope (TEM) called TEMGYM Basic is developed here, which enables users to understand how to operate and control an electron beam without the need to access an instrument. TEMGYM Basic allows users to familiarize themselves with alignment procedures offline, reducing the time and money required to become a proficient TEM operator. In addition to teaching the basics of electron beam alignments, the software enables users to create bespoke microscope configurations and develop an understanding of how to operate the configurations without sitting at a microscope. TEMGYM Basic also creates static ray diagram figures for a given lens configuration. The available components include apertures, lenses, quadrupoles, deflectors and biprisms. The software design uses first-order ray transfer matrices to calculate ray paths through each electron microscope component, and the program is developed entirely in Python to facilitate compatibility with machine-learning packages for future exploration of automated control.
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Affiliation(s)
- David Landers
- Department of Physics, University of Limerick, Limerick, Munster V94 T9PX, Ireland
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
| | - Ian Clancy
- Department of Physics, University of Limerick, Limerick, Munster V94 T9PX, Ireland
| | - Dieter Weber
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, Jülich, North Rhine-Westphalia 52428, Germany
| | - Rafal E. Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons (ER-C), Forschungszentrum Jülich, Wilhelm-Johnen-Straße, Jülich, North Rhine-Westphalia 52428, Germany
| | - Andrew Stewart
- Department of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, United Kingdom
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Gómez J, Tayebi A, Hellín CJ, Valledor A, Barranquero M, Cuadrado-Gallego JJ. Accelerated Ray Launching Method for Efficient Field Coverage Studies in Wide Urban Areas. Sensors (Basel) 2023; 23:6412. [PMID: 37514707 PMCID: PMC10383054 DOI: 10.3390/s23146412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 07/07/2023] [Accepted: 07/12/2023] [Indexed: 07/30/2023]
Abstract
The implementation of a fast and efficient computer tool for field coverage studies in urban mobile radio systems is presented in this work. An accelerated and tailored ray launching method takes advantage of a ray tracing programmable framework optimized for massively parallel processing on GPUs. The PlotOptiX API is used to customize the code before applying the electromagnetic equations. The proposed code is described, and results are shown to demonstrate its correct operation. A high number of diffractions and reflections can be tracked in each ray from the transmitter to the receiver. In addition to the typical point-to-point simulation, measurement planes can also be set as receivers to provide fast predictions in wide urban areas.
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Affiliation(s)
- Josefa Gómez
- Computer Sciences Department, University of Alcalá, 28801 Alcalá de Henares, Spain
| | - Abdelhamid Tayebi
- Computer Sciences Department, University of Alcalá, 28801 Alcalá de Henares, Spain
| | - Carlos J Hellín
- Computer Sciences Department, University of Alcalá, 28801 Alcalá de Henares, Spain
| | - Adrián Valledor
- Computer Sciences Department, University of Alcalá, 28801 Alcalá de Henares, Spain
| | - Marcos Barranquero
- Computer Sciences Department, University of Alcalá, 28801 Alcalá de Henares, Spain
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Verma S, Farrell DJ, Evans RC. Ray-Trace Modeling to Characterize Efficiency of Unconventional Luminescent Solar Concentrator Geometries. ACS Appl Opt Mater 2023; 1:1012-1025. [PMID: 37255505 PMCID: PMC10226161 DOI: 10.1021/acsaom.3c00074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 04/16/2023] [Indexed: 06/01/2023]
Abstract
Luminescent solar concentrators (LSCs) are a promising technology to help integrate solar cells into the built environment, as they are colorful, semitransparent, and can collect diffuse light. While LSCs have traditionally been cuboidal, in recent years, a variety of unconventional geometries have arisen, for example, circular, curved, polygonal, wedged, and leaf-shaped designs. These new designs can help reduce optical losses, facilitate incorporation into the built environment, or unlock new applications. However, as fabrication of complex geometries can be time- and resource-intensive, the ability to simulate the expected LSC performance prior to production would be highly advantageous. While a variety of software exists to model LSCs, it either cannot be applied to unconventional geometries, is not open-source, or is not tractable for most users. Therefore, here we introduce a significant upgrade of the widely used Monte Carlo ray-trace software pvtrace to include: (i) the capability to characterize unconventional geometries and improved relevance to standard measurement configurations; (ii) increased computational efficiency; and (iii) a graphical user interface (GUI) for ease-of-use. We first test these new features against data from the literature as well as experimental results from in-house fabricated LSCs, with agreement within 1% obtained for the simulated versus measured external photon efficiency. We then demonstrate the broad applicability of pvtrace by simulating 20 different unconventional geometries, including a variety of different shapes and manufacturing techniques. We show that pvtrace can be used to predict the optical efficiency of 3D-printed devices. The more versatile and accessible computational workflow afforded by our new features, coupled with 3D-printed prototypes, will enable rapid screening of more intricate LSC architectures, while reducing experimental waste. Our goal is that this accelerates sustainability-driven design in the LSC field, leading to higher optical efficiency or increased utility.
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Affiliation(s)
- Shomik Verma
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles Babbage Rd, Cambridge CB3 0FS, U.K.
| | - Daniel J Farrell
- Exciton
Labs, Copley Hill Business
Park, Cambridge Road, Babraham, Cambridge CB22 3GN, U.K.
| | - Rachel C. Evans
- Department
of Materials Science and Metallurgy, University
of Cambridge, 27 Charles Babbage Rd, Cambridge CB3 0FS, U.K.
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Retta MA, Yin X, Ho QT, Watté R, Berghuijs HNC, Verboven P, Saeys W, Cano FJ, Ghannoum O, Struik PC, Nicolaï BM. The role of chloroplast movement in C4 photosynthesis: A theoretical analysis using a 3-D reaction-diffusion model for maize. J Exp Bot 2023:7135625. [PMID: 37083863 PMCID: PMC10400148 DOI: 10.1093/jxb/erad138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Indexed: 05/03/2023]
Abstract
Chloroplasts movement within mesophyll (M) cells in C4 plants is hypothesized to enhance the CO2 concentrating mechanism (CCM), but this is difficult to verify experimentally. A three-dimensional (3-D) leaf model can help analyze how chloroplast movement influences the operation of CCM. The first volumetric reaction-diffusion model of C4 photosynthesis that incorporates: detailed 3-D leaf anatomy, light propagation, ATP and NADPH production and CO2, O2 and bicarbonate concentration driven by diffusional and assimilation/emission processes, was developed and implemented for maize leaves to simulate various chloroplast movement scenarios within M cells : the movement of all M chloroplasts towards bundle-sheath (BS) cells (aggregative movement) and movement of only those of interveinal M cells towards BS cells (avoidance movement). Light absorbed by bundle-sheath (BS) chloroplasts relative to M chloroplasts increased in both cases. Avoidance movement decreased light absorption by M chloroplasts considerably. Consequently, total ATP and NADPH production and net photosynthesis rate increased for aggregative movement and decreased for avoidance movement case compared to the default case of no chloroplast movement at high light intensities. Leakiness increased in both chloroplast movement scenarios due to the imbalance in energy production and demand in M and BS cells. These results suggest the need to design strategies for coordinated increases in electron transport and Rubisco activities for an efficient CCM at very high light intensities.
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Affiliation(s)
- M A Retta
- KU Leuven, MeBioS division, Willem de Croylaan 42, B-3001, Leuven, Belgium
- Centre for Crop Systems Analysis, Wageningen University & Research, P.O. Box 430, 6700 AK Wageningen, The Netherlands
| | - X Yin
- Centre for Crop Systems Analysis, Wageningen University & Research, P.O. Box 430, 6700 AK Wageningen, The Netherlands
| | - Q T Ho
- Institute of Marine Research, Nordnesgaten 50, NO-5005 Bergen, P.O. Box 1870, Nordnes, Norway
| | - R Watté
- KU Leuven, MeBioS division, Willem de Croylaan 42, B-3001, Leuven, Belgium
| | - H N C Berghuijs
- Plant Production Systems group, Wageningen University & Research, P.O. Box 430, 6700 AK Wageningen, The Netherlands
| | - P Verboven
- KU Leuven, MeBioS division, Willem de Croylaan 42, B-3001, Leuven, Belgium
| | - W Saeys
- KU Leuven, MeBioS division, Willem de Croylaan 42, B-3001, Leuven, Belgium
| | - F J Cano
- Centro de Investigación Forestal (CIFOR), Instituto Nacional de Investigacion y Tecnologia Agraria y Alimentaria (INIA), Consejo Superior de Investigaciones Científicas (CSIC), Carretera de la Coruña Km 7.5, 28040, Madrid, Spain
- ARC Centre of Excellence for Translational Photosynthesis, Hawkesbury Institute for the Environment, University of Western Sydney, Hawkesbury campus, Locked Bag 1797, Penrith 2751, NSW, Australia
| | - O Ghannoum
- ARC Centre of Excellence for Translational Photosynthesis, Hawkesbury Institute for the Environment, University of Western Sydney, Hawkesbury campus, Locked Bag 1797, Penrith 2751, NSW, Australia
| | - P C Struik
- Centre for Crop Systems Analysis, Wageningen University & Research, P.O. Box 430, 6700 AK Wageningen, The Netherlands
| | - B M Nicolaï
- KU Leuven, MeBioS division, Willem de Croylaan 42, B-3001, Leuven, Belgium
- Flanders Center of Postharvest Technology, Willem de Croylaan 42, B-3001, Leuven, Belgium
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Makara ÁL, Csathó BT, Rácz A, Borsos T, Csurgai-Horváth L, Horváth BP. Deep-Learning-Based Antenna Alignment Prediction for Mobile Indoor Communication. Sensors (Basel) 2023; 23:3375. [PMID: 37050434 PMCID: PMC10098692 DOI: 10.3390/s23073375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/05/2023] [Accepted: 03/17/2023] [Indexed: 06/19/2023]
Abstract
A significant innovation for future indoor wireless networks is the use of the mmWave frequency band. However, an important challenge comes from the restricted propagation conditions in this band, which necessitates the use of beamforming and associated beam management procedures, including, for instance, beam tracking or beam prediction. A possible solution to the beam management problem is to use artificial-intelligence-based procedures to learn the hidden spatial propagation patterns of the channel and to use this knowledge to predict the best beam directions. In this paper, we present a deep-neural-network-based method that has memory that can be used to predict the best reception directions for moving users. The best direction is the highest expected signal level at the next moment. The resulting method allows for a user-side antenna management system. The result was evaluated using three different metrics, thus detailing not only its predictive ability, but also its usability.
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Affiliation(s)
- Árpád László Makara
- Department of Broadband Infocommunications and Electromagnetic Theory, Faculty of Electrical Engineering and Informatics, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
| | - Botond Tamás Csathó
- Department of Broadband Infocommunications and Electromagnetic Theory, Faculty of Electrical Engineering and Informatics, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
| | | | | | - László Csurgai-Horváth
- Department of Broadband Infocommunications and Electromagnetic Theory, Faculty of Electrical Engineering and Informatics, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
| | - Bálint Péter Horváth
- Department of Broadband Infocommunications and Electromagnetic Theory, Faculty of Electrical Engineering and Informatics, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary
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Zhang C, Cui S, Wang S, Hu J, Huangfu Y, Zhang B. High-Precision 3D Reconstruction Study with Emphasis on Refractive Calibration of GelStereo-Type Sensors. Sensors (Basel) 2023; 23:2675. [PMID: 36904879 PMCID: PMC10007575 DOI: 10.3390/s23052675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 02/21/2023] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
GelStereo sensing technology is capable of performing three-dimensional (3D) contact shape measurement under various contact structures such as bionic curved surfaces, which has promising advantages in the field of visuotactile sensing. However, due to multi-medium ray refraction in the imaging system, robust and high-precision tactile 3D reconstruction remains a challenging problem for GelStereo-type sensors with different structures. In this paper, we first propose a universal Refractive Stereo Ray Tracing (RSRT) model for GelStereo-type sensing systems to realize 3D reconstruction of the contact surface. Moreover, a relative geometry-based optimization method is presented to calibrate multiple parameters of the proposed RSRT model, such as the refractive indices and structural dimensions. Furthermore, extensive quantitative calibration experiments are performed on four different GelStereo sensing platforms; the experimental results show that the proposed calibration pipeline can achieve less than 0.35 mm in Euclidean distance error, based on which we believe that the proposed refractive calibration method can be further applied in more complex GelStereo-type and other similar visuotactile sensing systems. Such high-precision visuotactile sensors can facilitate the study of robotic dexterous manipulation.
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Affiliation(s)
- Chaofan Zhang
- State Key Laboratory of Multimodal Artificial Intelligence Systems, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
- School of Artificial Intelligence, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shaowei Cui
- State Key Laboratory of Multimodal Artificial Intelligence Systems, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Shuo Wang
- State Key Laboratory of Multimodal Artificial Intelligence Systems, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
- School of Artificial Intelligence, University of Chinese Academy of Sciences, Beijing 100049, China
- Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jingyi Hu
- State Key Laboratory of Multimodal Artificial Intelligence Systems, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
- School of Future Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yipeng Huangfu
- Faculty of Information Technology, Beijing University of Technology, Beijing 100124, China
| | - Boyue Zhang
- State Key Laboratory of Multimodal Artificial Intelligence Systems, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
- School of Artificial Intelligence, University of Chinese Academy of Sciences, Beijing 100049, China
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Schipper R, van der Meer M, de Visser P, Heuvelink E, Marcelis L. Consequences of intra-canopy and top LED lighting for uniformity of light distribution in a tomato crop. Front Plant Sci 2023; 14:1012529. [PMID: 36743509 PMCID: PMC9893118 DOI: 10.3389/fpls.2023.1012529] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 01/04/2023] [Indexed: 06/18/2023]
Abstract
In the past decade, the potential of positioning LED lamps in between the canopy (intra-canopy) to enhance crop growth and yield has been explored in greenhouse cultivation. Changes in spatial heterogeneity of light absorption that come with the introduction of intra-canopy lighting have not been thoroughly explored. We calibrated and validated an existing functional structural plant model (FSPM), which combines plant morphology with a ray tracing model to estimate light absorption at leaflet level. This FSPM was used to visualize the light environment in a tomato crop illuminated with intra-canopy lighting, top lighting or a combination of both. Model validation of light absorption of individual leaves showed a good fit (R2 = 0.93) between measured and modelled light absorption of the canopy. Canopy light distribution was then quantified and visualized in three voxel directions by means of average absorbed photosynthetic photon flux density (PPFD) and coefficient of variation (CV) within that voxel. Simulations showed that the variation coefficient within horizontal direction was higher for intra-canopy lighting than top lighting (CV=48% versus CV= 43%), while the combination of intra-canopy lighting and top lighting yielded the lowest CV (37%). Combined intra-canopy and top lighting (50/50%) had in all directions a more uniform light absorption than intra-canopy or top lighting alone. The variation was minimal when the ratio of PPFD from intra-canopy to top lighting was about 1, and increased when this ratio increased or decreased. Intra-canopy lighting resulted in 8% higher total light absorption than top lighting, while combining 50% intra-canopy lighting with 50% top lighting, increased light absorption by 4%. Variation in light distribution was further reduced when the intra-canopy LEDs were distributed over strings at four instead of two heights. When positioning LED lamps to illuminate a canopy both total light absorption and light distribution have to be considered.
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Affiliation(s)
- R. Schipper
- Horticulture and Product Physiology, Wageningen University, Wageningen, Netherlands
| | - M. van der Meer
- Horticulture and Product Physiology, Wageningen University, Wageningen, Netherlands
| | - P.H.B. de Visser
- Business Unit Greenhouse Horticulture, Wageningen Research, Wageningen, Netherlands
| | - E. Heuvelink
- Horticulture and Product Physiology, Wageningen University, Wageningen, Netherlands
| | - L.F.M. Marcelis
- Horticulture and Product Physiology, Wageningen University, Wageningen, Netherlands
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Kim E, Choi S, Kim CG, Park WC. Multi-Threaded Sound Propagation Algorithm to Improve Performance on Mobile Devices. Sensors (Basel) 2023; 23:973. [PMID: 36679768 PMCID: PMC9864067 DOI: 10.3390/s23020973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 01/11/2023] [Accepted: 01/12/2023] [Indexed: 06/17/2023]
Abstract
We propose a multi-threaded algorithm that can improve the performance of geometric acoustic (GA)-based sound propagation algorithms in mobile devices. In general, sound propagation algorithms require high computational cost because they perform based on ray tracing algorithms. For this reason, it is difficult to operate sound propagation algorithms in mobile environments. To solve this problem, we processed the early reflection and late reverberation steps in parallel and verified the performance in four scenes based on eight sound sources. The experimental results showed that the performance of the proposed method was on average 1.77 times better than that of the single-threaded method, demonstrating that our algorithm can improve the performance of mobile devices.
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Affiliation(s)
- Eunjae Kim
- Department of Computer Science and Engineering, Sejong University, Seoul 05006, Republic of Korea
| | - Sukwon Choi
- Department of Computer Science and Engineering, Sejong University, Seoul 05006, Republic of Korea
| | - Cheong Ghil Kim
- Department of Computer Science, Namseoul University, Cheonan 31020, Republic of Korea
| | - Woo-Chan Park
- Department of Computer Science and Engineering, Sejong University, Seoul 05006, Republic of Korea
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13
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Fakhri D, Alidoust F, Rostami A, Mirtaheri P. A Monte-Carlo/FDTD Study of High-Efficiency Optical Antennas for LED-Based Visible Light Communication. Nanomaterials (Basel) 2022; 12:3594. [PMID: 36296783 PMCID: PMC9606907 DOI: 10.3390/nano12203594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 09/29/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
In high-speed wireless communication, visible light communication is considered an emerging and cutting-edge technology. A light-emitting diode can serve both as an illumination source in an environment and as a data transmitter. Nevertheless, plenty of complications stand in the way of developing VLC technology, including the low response time of waveguides and detectors and the field of view dependence of such devices. To cover those challenges, one approach is to develop a superior optical antenna that does not have a low response time related to phosphorescence materials and should also support concentrating light from the surroundings with a wide field of view. This research paper presents an optimized cylindrical optical antenna with benefits, such as affordable cost, fast response time due to high-efficient nanomaterials, and a wide field of view (FOV). The proposed structure avoids the need for intricate tracking systems and active pointing to the source, but it can also be integrated into portable devices. For the analysis of nanomaterials' characteristics, finite difference time domain simulations are used, and Monte-Carlo raytracing is used to study the proposed optical antenna. It was found that the antenna's optical efficiency varies from 1 to 29% depending on the size and the number of nanomaterials inside. Compared to other works, this paper shows higher efficiencies and wider FOV.
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Affiliation(s)
- Darya Fakhri
- OIC Research Group, Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz 5166614761, Iran
| | - Farid Alidoust
- OIC Research Group, Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz 5166614761, Iran
| | - Ali Rostami
- OIC Research Group, Faculty of Electrical and Computer Engineering, University of Tabriz, Tabriz 5166614761, Iran
- SP-EPT Laboratory, ASEPE Company, Industrial Park of Advanced Technologies, Tabriz 5364196795, Iran
| | - Peyman Mirtaheri
- Department of Mechanical, Electronics and Chemical Engineering, OsloMet—Oslo Metropolitan University, 0167 Oslo, Norway
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14
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Mikeházi A, El Guettioui J, Földes IB, Vankó G, Németh Z. Multicolor single-analyzer high-energy-resolution XES spectrometer for simultaneous examination of different elements. J Synchrotron Radiat 2022; 29:1216-1222. [PMID: 36073880 PMCID: PMC9455214 DOI: 10.1107/s1600577522007561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
The present work demonstrates the performance of a von Hámos high-energy-resolution X-ray spectrometer based on a non-conventional conical Si single-crystal analyzer. The analyzer is tested with different primary and secondary X-ray sources as well as a hard X-ray sensitive CCD camera. The spectrometer setup is also characterized with ray-tracing simulations. Both experimental and simulated results affirm that the conical spectrometer can efficiently detect and resolve the two pairs of two elements (Ni and Cu) Kα X-ray emission spectroscopy (XES) peaks simultaneously, requiring a less than 2 cm-wide array on a single position-sensitive detector. The possible applications of this simple yet broad-energy-spectrum crystal spectrometer range from quickly adapting it as another probe for complex experiments at synchrotron beamlines to analyzing X-ray emission from plasma generated by ultrashort laser pulses at modern laser facilities.
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Affiliation(s)
- Antal Mikeházi
- Wigner Research Centre for Physics, Konkoly Thege M. 29-33, 1121 Budapest, Hungary
| | - Jihad El Guettioui
- Wigner Research Centre for Physics, Konkoly Thege M. 29-33, 1121 Budapest, Hungary
| | - István B. Földes
- Wigner Research Centre for Physics, Konkoly Thege M. 29-33, 1121 Budapest, Hungary
| | - György Vankó
- Wigner Research Centre for Physics, Konkoly Thege M. 29-33, 1121 Budapest, Hungary
| | - Zoltán Németh
- Wigner Research Centre for Physics, Konkoly Thege M. 29-33, 1121 Budapest, Hungary
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15
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Yu XJ, Chi X, Smulders T, Wee ATS, Rusydi A, Sanchez del Rio M, Breese MBH. Beamline simulations using monochromators with high d-spacing crystals. J Synchrotron Radiat 2022; 29:1157-1166. [PMID: 36073874 PMCID: PMC9455208 DOI: 10.1107/s160057752200707x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 07/10/2022] [Indexed: 06/15/2023]
Abstract
Monochromators for synchrotron radiation beamlines typically use perfect crystals for the hard X-ray regime and gratings for soft X-rays. There is an intermediate range, typically 1-3 keV (tender X-rays), which common perfect crystals have difficulties covering and gratings have low efficiency, although some less common crystals with high d-spacing could be suitable. To evaluate the suitability of these crystals for a particular beamline, it is useful to evaluate the crystals' performance using tools such as ray-tracing. However, simulations for double-crystal monochromators are only available for the most used crystals such as Si, Ge or diamond. Here, an upgrade of the SHADOW ray-tracing code and complementary tools in the OASYS suite are presented to simulate high d-spacing crystals with arbitrary, and sometimes complex, structures such as beryl, YB66, muscovite, etc. Isotropic and anisotropic temperature factors are also considered. The YB66 crystal with 1936 atomic sites in the unit cell is simulated, and its applicability for tender X-ray monochromators is discussed in the context of new low-emittance storage rings.
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Affiliation(s)
- X. J. Yu
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603, Singapore
| | - X. Chi
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603, Singapore
- Department of Physics, National University of Singapore, Singapore 117576, Singapore
| | - T. Smulders
- Department of Engineering Physics, Fonty University of Applied Sciences, 5615DB Eindhoven, The Netherlands
| | - A. T. S. Wee
- Department of Physics, National University of Singapore, Singapore 117576, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore
- NUS Graduate School for Integrative Sciences and Engineering, Singapore 117456, Singapore
| | - A. Rusydi
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603, Singapore
- Department of Physics, National University of Singapore, Singapore 117576, Singapore
- Centre for Advanced 2D Materials and Graphene Research Centre, National University of Singapore, Singapore 117546, Singapore
- NUS Graduate School for Integrative Sciences and Engineering, Singapore 117456, Singapore
| | | | - M. B. H. Breese
- Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603, Singapore
- Department of Physics, National University of Singapore, Singapore 117576, Singapore
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Kraus D, Diwold K, Pestana J, Priller P, Leitgeb E. Towards a Recommender System for In-Vehicle Antenna Placement in Harsh Propagation Environments. Sensors (Basel) 2022; 22:6339. [PMID: 36080797 PMCID: PMC9460237 DOI: 10.3390/s22176339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 08/09/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
This paper presents a novel approach to improving wireless communications in harsh propagation environments to achieve higher overall reliability and durability of wireless battery powered sensor systems in the context of in-vehicle communication. The goal is to investigate the physical layer and establish an antenna recommendation system for a specific harsh environment, i.e., an engine compartment of a vehicle. We propose the usage of electromagnetic (EM) and ray tracing simulations as a computationally cost-effective method to establish such a recommendation system, which we test by means of an experimental testbed-or test environment-that consists of both a physical, as well as its identical simulation, model. A pool of antennas is evaluated to identify and verify antenna behavior and properties at specified positions in the harsh environment. We use a vector network analyzer (VNA) for accurate measurements and a received signal strength indicator (RSSI) for a first estimation of system performance. Our analysis of the experimental measurements and its EM simulation counterparts shows that both types of data lead to equivalent antenna recommendations at each of the defined positions and experimental conditions. This evaluation and verification process by measurements on an experimental testbed is important to validate the antenna recommendation process. Our results indicate that-with properly characterized antennas-such measurements can be substituted with EM simulations on an accurate EM model, which can contribute to dramatically speeding up the antenna positioning and selection process.
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Affiliation(s)
| | - Konrad Diwold
- Pro2Future GmbH, 8010 Graz, Austria
- Institute of Technical Informatics, Graz University of Technology, 8010 Graz, Austria
| | | | | | - Erich Leitgeb
- Institute of Microwave and Photonic Engineering, Graz University of Technology, 8010 Graz, Austria
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17
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Guo Z, Yang B, Liang Y, Huang Z. Virtual Simulation of the Effect of FMCW Laser Fuse Detector's Component Performance Variability on Target Echo Characteristics under Smoke Interference. Materials (Basel) 2022; 15:ma15124268. [PMID: 35744327 PMCID: PMC9229106 DOI: 10.3390/ma15124268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/09/2022] [Accepted: 06/14/2022] [Indexed: 12/10/2022]
Abstract
The laser transmitter and photoelectric receiver are the core modules of the detector in a laser proximity fuse, whose performance variability can affect the accuracy of target detection and identification. In particular, there is no study on the effect of detector’s component performance variability on frequency-modulated continuous-wave (FMCW) laser fuse under smoke interference. Therefore, based on the principles of particle dynamic collision, ray tracing, and laser detection, this paper builds a virtual simulation model of FMCW laser transmission with the professional particle system of Unity3D, and studies the effect of performance variability of laser fuse detector components on the target characteristics under smoke interference. Simulation results show that the difference in the performance of the fuse detector components causes the amplitude variation and peak migration of the beat signal spectrum, and the change in the visibility of the smoke can also affect the results, which indicates that the factors affecting the signal-to-noise ratio (SNR) of the echo signal are related to the smoke interference and performance variability of the detector. The proposed simulation model is supported by experimental results, which reflect the reliability of the proposed findings. Therefore, this study can be used for the optimization of the parameters in the laser fuse antismoke interference to avoid false alarms.
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18
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Qian J, Wu Y, Saleem A, Zheng G. Path Loss Model for 3.5 GHz and 5.6 GHz Bands in Cascaded Tunnel Environments. Sensors (Basel) 2022; 22:4524. [PMID: 35746306 DOI: 10.3390/s22124524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 06/06/2022] [Accepted: 06/13/2022] [Indexed: 12/04/2022]
Abstract
An important and typical scenario of radio propagation in a railway or subway tunnel environment is the cascaded straight and curved tunnel. In this paper, we propose a joint path loss model for cascaded tunnels at 3.5 GHz and 5.6 GHz frequency bands. By combining the waveguide mode theory and the method of shooting and bouncing ray (SBR), it is found that the curvature of tunnels introduces an extra loss in the far-field region, which can be modeled as a linear function of the propagation distance of the signal in the curved tunnel. The channel of the cascaded straight and curved tunnel is thus characterized using the extra loss coefficient (ELC). Based on the ray-tracing (RT) method, an empirical formula between ELC and the radius of the curvature is provided for 3.5 GHz and 5.6 GHz, respectively. Finally, the accuracy of the proposed model is verified by measurement and simulation results. It is shown that the proposed model can predict path loss in cascaded tunnels with desirable accuracy and low complexity.
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19
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Adam DP, Bednarz BP, Frigo SP. Static MLC transmission simulation using two-dimensional ray tracing. J Appl Clin Med Phys 2022; 23:e13646. [PMID: 35596533 PMCID: PMC9359033 DOI: 10.1002/acm2.13646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 04/08/2022] [Accepted: 04/28/2022] [Indexed: 11/10/2022] Open
Abstract
Purpose We investigated the hypothesis that the transmission function of rounded end linearly traveling multileaf collimators (MLCs) is constant with position. This assumption is made by some MLC models used in clinical treatment planning systems (TPSs) and in the Varian MLC calibration convention. If not constant, this would have implications for treatment plan QA results. Methods A two‐dimensional ray‐tracing tool to generate transmission curves as a function of leaf position was created and validated. The curves for clinically available leaf tip positions (−20 to 20 cm) were analyzed to determine the location of the beam edge (half‐attenuation X‐ray [XR]) location, the beam edge broadening (BEB, 80%–20% width), as well as the leaf tip zone width. More generalized scenarios were then simulated to elucidate trends as a function of leaf tip radius. Results In the analysis of the Varian high‐definition MLC, two regions were identified: a quasi‐static inner region centered about central axis (CAX), and an outer one, in which large deviations were observed. A phenomenon was identified where the half‐attenuation ray position, relative to that of the tip or tangential ray, increases dramatically at definitive points from CAX. Similar behavior is seen for BEB. An analysis shows that as the leaf radius parameter value is made smaller, the size of the quasi‐static region is greater (and vice versa). Conclusion The MLC transmission curve properties determined by this study have implications both for MLC position calibrations and modeling within TPSs. Two‐dimensional ray tracing can be utilized to identify where simple behaviors hold, and where they deviate. These results can help clinical physicists engage with vendors to improve MLC models, subsequent fluence calculations, and hence dose calculation accuracy.
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Affiliation(s)
- David P Adam
- Department of Medical Physics, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Bryan P Bednarz
- Department of Medical Physics, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
| | - Sean P Frigo
- Department of Human Oncology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin, USA
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20
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Kallepalli A, Halls J, James DB, Richardson MA. An ultrasonography-based approach for tissue modelling to inform photo-therapy treatment strategies. J Biophotonics 2022; 15:e202100275. [PMID: 35044094 DOI: 10.1002/jbio.202100275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 06/14/2023]
Abstract
Currently, diagnostic medicine uses a multitude of tools ranging from ionising radiation to histology analysis. With advances in piezoelectric crystal technology, high-frequency ultrasound imaging has developed to achieve comparatively high resolution without the drawbacks of ionising radiation. This research proposes a low-cost, non-invasive and real-time protocol for informing photo-therapy procedures using ultrasound imaging. We combine currently available ultrasound procedures with Monte Carlo methods for assessing light transport and photo-energy deposition in the tissue. The measurements from high-resolution ultrasound scans are used as input for optical simulations. Consequently, this provides a pipeline that will inform medical practitioners for better therapy strategy planning. While validating known inferences of light transport through biological tissue, our results highlight the range of information such as temporal monitoring and energy deposition at varying depths. This process also retains the flexibility of testing various wavelengths for individual-specific geometries and anatomy.
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Affiliation(s)
- Akhil Kallepalli
- School of Physics and Astronomy, University of Glasgow, Glasgow, UK
| | - James Halls
- Department of Radiology, The Great Western Hospital, Swindon, UK
| | - David B James
- Centre for Electronic Warfare, Information and Cyber, Cranfield University, Defence Academy of the UK, Shrivenham, UK
| | - Mark A Richardson
- Centre for Electronic Warfare, Information and Cyber, Cranfield University, Defence Academy of the UK, Shrivenham, UK
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21
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Ashena Z, Gallagher S, Naveed H, Spalton DJ, Nanavaty MA. Comparison of Anterior Corneal Aberrometry, Keratometry and Pupil Size with Scheimpflug Tomography and Ray Tracing Aberrometer. Vision (Basel) 2022; 6. [PMID: 35324603 DOI: 10.3390/vision6010018] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 03/15/2022] [Accepted: 03/16/2022] [Indexed: 11/17/2022] Open
Abstract
This study aimed to assess the anterior corneal wavefront aberrations, keratometry, astigmatism vectors and pupil size between Pentacam HR® (Oculus Optikgeraete GmbH, Wetzlar, Germany) and iTrace® (Tracey Technologies Corp., Houston, TX, USA). In this observational study, 100 eyes (50 healthy volunteers) were scanned in mesopic light condition with a Pentacam HR® and iTrace®. Anterior corneal aberrations (spherical aberration (Z40), vertical coma (Z3 − 1), horizontal coma (Z3 + 1)), keratometry in the flattest (K1) and steepest meridian (K2), mean astigmatism, astigmatic vectors (J0 and J45), and pupil size were measured. We found a significant difference in Z40 (Pentacam®: +0.30 ± 0.11 µm and iTrace®: −0.03 µm ± 0.05 µm; p < 0.01) with no correlation between the devices (r = −0.12, p = 0.22). The devices were in complete agreement for Z3 − 1 (p = 0.78) and Z3 + 1 (p = 0.39), with significant correlation between the machines (r = −0.38, p < 0.01 and r = −0.6, p < 0.01). There was no difference in K1, K2 and mean astigmatism. J0 was negative with both devices (against-the-rule astigmatism), but there was no correlation. J45 was negative with the Pentacam HR® (more myopic oblique astigmatism) but significantly correlated between the devices. Pupil size was smaller with Pentacam HR® (p < 0.01). In summary, these devices cannot be used interchangeably. Corneal Z40 was significantly different with more negative Z40 with iTrace® compared to Pentacam HR®. iTrace® operates with lower illumination, giving larger pupil size than Pentacam HR®, which uses intense blue light during measurement. No correlation was found for J0. Pentacam HR® had a trend to record more negative J45 (myopic oblique astigmatism).
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22
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Mulkerns NMC, Hoffmann WH, Lindsay ID, Gersen H. Shedding Light on Capillary-Based Backscattering Interferometry. Sensors (Basel) 2022; 22:2157. [PMID: 35336326 DOI: 10.3390/s22062157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/02/2022] [Accepted: 03/08/2022] [Indexed: 02/05/2023]
Abstract
Capillary-based backscattering interferometry has been used extensively as a tool to measure molecular binding via interferometric refractive index sensing. Previous studies have analysed the fringe patterns created in the backscatter direction. However, polarisation effects, spatial chirps in the fringe pattern and the practical impact of various approximations, and assumptions in existing models are yet to be fully explored. Here, two independent ray tracing approaches are applied, analysed, contrasted, compared to experimental data, and improved upon by introducing explicit polarisation dependence. In doing so, the significance of the inner diameter, outer diameter, and material of the capillary to the resulting fringe pattern and subsequent analysis are elucidated for the first time. The inner diameter is shown to dictate the fringe pattern seen, and therefore, the effectiveness of any dechirping algorithm, demonstrating that current dechirping methods are only valid for a subset of capillary dimensions. Potential improvements are suggested in order to guide further research, increase sensitivity, and promote wider applicability.
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23
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Konvalina I, Paták A, Zouhar M, Müllerová I, Fořt T, Unčovský M, Materna Mikmeková E. Quantification of STEM Images in High Resolution SEM for Segmented and Pixelated Detectors. Nanomaterials (Basel) 2021; 12:71. [PMID: 35010021 PMCID: PMC8746443 DOI: 10.3390/nano12010071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 12/24/2021] [Accepted: 12/24/2021] [Indexed: 06/14/2023]
Abstract
The segmented semiconductor detectors for transmitted electrons in ultrahigh resolution scanning electron microscopes allow observing samples in various imaging modes. Typically, two standard modes of objective lens, with and without a magnetic field, differ by their resolution. If the beam deceleration mode is selected, then an electrostatic field around the sample is added. The trajectories of transmitted electrons are influenced by the fields below the sample. The goal of this paper is a quantification of measured images and theoretical study of the capability of the detector to collect signal electrons by its individual segments. Comparison of measured and ray-traced simulated data were difficult in the past. This motivated us to present a new method that enables better comparison of the two datasets at the cost of additional measurements, so-called calibration curves. Furthermore, we also analyze the measurements acquired using 2D pixel array detector (PAD) that provide a more detailed angular profile. We demonstrate that the radial profiles of STEM and/or 2D-PAD data are sensitive to material composition. Moreover, scattering processes are affected by thickness of the sample as well. Hence, comparing the two experimental and simulation data can help to estimate composition or the thickness of the sample.
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Affiliation(s)
- Ivo Konvalina
- Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 612 64 Brno, Czech Republic; (A.P.); (M.Z.); (I.M.); (T.F.); (E.M.M.)
| | - Aleš Paták
- Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 612 64 Brno, Czech Republic; (A.P.); (M.Z.); (I.M.); (T.F.); (E.M.M.)
| | - Martin Zouhar
- Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 612 64 Brno, Czech Republic; (A.P.); (M.Z.); (I.M.); (T.F.); (E.M.M.)
| | - Ilona Müllerová
- Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 612 64 Brno, Czech Republic; (A.P.); (M.Z.); (I.M.); (T.F.); (E.M.M.)
| | - Tomáš Fořt
- Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 612 64 Brno, Czech Republic; (A.P.); (M.Z.); (I.M.); (T.F.); (E.M.M.)
| | - Marek Unčovský
- Thermo Fisher Scientific Inc., Vlastimila Pecha 12, 627 00 Brno, Czech Republic;
| | - Eliška Materna Mikmeková
- Institute of Scientific Instruments of the Czech Academy of Sciences, Královopolská 147, 612 64 Brno, Czech Republic; (A.P.); (M.Z.); (I.M.); (T.F.); (E.M.M.)
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Fernández-Rosés J, Lamarca J, Piñero DP, Barraquer RI. Intraocular lens power calculation in virgin eyes: Accuracy of the Barrett Universal II formula and a Ray tracing software. Eur J Ophthalmol 2021; 32:2954-2960. [PMID: 34854773 DOI: 10.1177/11206721211065552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE To compare the accuracy of Sirius ray tracing software with the Barrett Universal II formula for intraocular lens power prediction in virgin eyes. METHODS Retrospective case series including 86 eyes that have undergone uneventful cataract surgery with SN60WF implantation. The median absolute error, mean prediction error, variance, and the percentage of eyes within ± 0.25 D, ± 0.50 D, ± 0.75 D, and ± 1.00 D of the prediction error in refraction were calculated. The correlation of prediction error with different baseline parameters was investigated. RESULTS No differences were found between the median absolute error of the Barrett Universal II formula (0.226 D) and the ray tracing software with different intraocular lens centerings; apex (0.331 D), limbus (0.345 D), and pupil (0.342 D) (p = 0.084). The variance, from lowest to highest, was the Barrett Universal II (0.144 D2), ray tracing-limbus (0.285 D2), ray tracing-pupil (0.285 D2), and ray tracing-apex (0.287 D2) (p = 0.027). The Barrett Universal II formula showed a higher percentage of eyes within ± 0.25 D (56.98%), ± 0.50 D (82.56%), and ± 0.75 D (93.02%) compared to ray tracing software (p < 0.01). A significant correlation between the prediction error of the Barrett Universal II formula and corneal diameter (r = 0.322, p = 0.002) and pupil diameter (r = 0.230, p = 0.033) was found. Also, a positive correlation between the prediction error of Sirius ray tracing and axial length (p < 0.001) and pupil diameter (p = 0.01) was found. CONCLUSION There is a trend of the Barrett Universal II formula to be more accurate than Sirius ray tracing software for intraocular lens power calculation in virgin eyes. This should be confirmed in future prospective comparative studies.
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Affiliation(s)
- Joaquim Fernández-Rosés
- 16360Centro de Oftalmología Barraquer, Barcelona, Spain.,Institut Universitari Barraquer, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - José Lamarca
- 16360Centro de Oftalmología Barraquer, Barcelona, Spain.,Institut Universitari Barraquer, Universitat Autònoma de Barcelona, Barcelona, Spain.,16760Universitat Internacional de Catalunya, Barcelona, Spain
| | - David P Piñero
- Department of Optics, Pharmacology and Anatomy, 16718University of Alicante, Alicante, Spain
| | - Rafael I Barraquer
- 16360Centro de Oftalmología Barraquer, Barcelona, Spain.,Institut Universitari Barraquer, Universitat Autònoma de Barcelona, Barcelona, Spain.,16760Universitat Internacional de Catalunya, Barcelona, Spain
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Lin TY, Wu CY. Numerical Investigation of a Designed-Inlet Optofluidic Beam Splitter for Split-Angle and Transmission Improvement. Micromachines (Basel) 2021; 12:1200. [PMID: 34683248 DOI: 10.3390/mi12101200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 09/26/2021] [Accepted: 09/28/2021] [Indexed: 11/16/2022]
Abstract
The beam splitter is one of the important elements in optical waveguide circuits. To improve the performance of an optofluidic beam splitter, a microchannel including a two-stage main channel with divergent side walls and two pairs of inlet channels is proposed. Besides, the height of the inlets injected with cladding fluid is set to be less than the height of other parts of the microchannel. When we inject calcium chloride solution (cladding fluid) and deionized water (core fluid) into the inlet channels, the gradient refractive index (GRIN) developed in fluids flowing through the microchannel splits the incident light beam into two beams with a larger split angle. Moreover, the designed inlets yield a GRIN distribution which increases the light collected around the middle horizontal line on the objective plane, and so enhances the transmission efficiency of the device. To demonstrate the performance of the proposed beam splitter, we use polydimethylsiloxane to fabricate the microchannel. The results obtained by simulation and experiment are compared to show the effectiveness of the device and the validity of numerical simulation. The influence of the microchannel geometry and the flow rate ratio on the performance of the proposed beam splitter is investigated.
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Sanchez Del Rio M, Goldberg KA, Yashchuk VV, Lacey I, Padmore HA. Simulations of applications using diaboloid mirrors. J Synchrotron Radiat 2021; 28:1041-1049. [PMID: 34212867 DOI: 10.1107/s160057752100401x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 04/14/2021] [Indexed: 06/13/2023]
Abstract
The diaboloid is a reflecting surface that converts a spherical wave to a cylindrical wave. This complex surface may find application in new Advanced Light Source bending-magnet beamlines or in other beamlines that now use toroidal optics for astigmatic focusing. Here, the numerical implementation of diaboloid mirrors is described, and the benefit of this mirror in beamlines exploiting diffraction-limited storage rings is studied by ray tracing. The use of diaboloids becomes especially interesting for the new low-emittance storage rings because the reduction of aberration becomes essential for such small sources. The validity of the toroidal and other mirror surfaces approximating the diaboloid, and the effect of the mirror magnification, are discussed.
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Affiliation(s)
| | | | | | - Ian Lacey
- Advanced Light Source, LBNL, Berkeley, CA, USA
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Semeniuk O, Cherpak A, Robar J. Design and evaluation of 3D printable patient-specific applicators for gynecologic HDR brachytherapy. Med Phys 2021; 48:4053-4063. [PMID: 33880777 DOI: 10.1002/mp.14888] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 03/17/2021] [Accepted: 04/01/2021] [Indexed: 01/13/2023] Open
Abstract
PURPOSE The purpose of this study is to improve dose distribution and organ-at-risk sparing during gynecologic HDR brachytherapy with patient-specific applicators. The majority of applicators used today are generic in design and do not allow for dose modulation for patient-specific shaping of dose distributions. Their performance might be adjusted with commercially available wedge shields; however, this provides dose modulation in the orthogonal plane only and does not allow for variation along the length of the applicator. Generic applicators are available only in standard sizes and geometries, and provide suboptimal patient fit with limited dose modulation. METHODS In this paper we use Monte Carlo modeling for comprehensive characterization of radiologic properties of various 3D printable biocompatible and sterilizable materials with comparison to water. Based on these results, we choose the optimal set of materials for a patient-specific applicator. We develop a novel method to design the patient-specific applicator without incurring a significant increase in treatment time or changes to clinical workflow. Finally, using an example of two selected vaginal cancers, we compare the performance of patient-specific and water-equivalent applicators in terms of target coverage and rectum sparing. RESULTS In the energy range from 1 MeV to 4 MeV, all materials have similar attenuation coefficients. In the range from ~2 keV to 1 MeV and above 4 MeV, tungsten-polylactic acid composite (WPLA) was seen to have the highest attenuation coefficient. The dose distribution of the water-equivalent applicator was found to be symmetric about its central axis. At the same time patient-specific shielded applicators exhibit well-modulated dose distributions. Their isodose lines are seen to spread radially into the patient, while merging close to the applicator surface, where WPLA shielding has been applied. CONCLUSIONS The patient-specific cylinders provide comparable dose to the target, while offering advanced healthy tissue sparing, not achievable with the generic design.
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Affiliation(s)
- Oleksii Semeniuk
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, M5G 1X6, Canada
| | - Amanda Cherpak
- Medical Physics, Nova Scotia Health, Halifax, B3H 1V7, Canada.,Department of Radiation Oncology, Dalhousie University, Halifax, B3H 4R2, Canada.,Department of Physics & Atmospheric Science, Dalhousie University, Halifax, B3H 4R2, Canada
| | - James Robar
- Medical Physics, Nova Scotia Health, Halifax, B3H 1V7, Canada.,Department of Radiation Oncology, Dalhousie University, Halifax, B3H 4R2, Canada.,Department of Physics & Atmospheric Science, Dalhousie University, Halifax, B3H 4R2, Canada
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Sheikh MU, Xie B, Ruttik K, Yiğitler H, Jäntti R, Hämäläinen J. Ultra-Low-Power Wide Range Backscatter Communication Using Cellular Generated Carrier. Sensors (Basel) 2021; 21:2663. [PMID: 33920074 DOI: 10.3390/s21082663] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/02/2021] [Accepted: 04/07/2021] [Indexed: 11/18/2022]
Abstract
With the popularization of Internet-of-things (IoT) and wireless communication systems, a diverse set of applications in smart cities are emerging to improve the city-life. These applications usually require a large coverage area and minimal operation and maintenance cost. To this end, the recently emerging backscatter communication (BC) is gaining interest in both industry and academia as a new communication paradigm that provides high energy efficient communications that may even work in a battery-less mode and, thus, it is well suited for smart city applications. However, the coverage of BC in urban area deployments is not available, and the feasibility of its utilization for smart city applications is not known. In this article, we present a comprehensive coverage study of a practical cellular carrier-based BC system for indoor and outdoor scenarios in a downtown area of a Helsinki city. In particular, we evaluate the coverage outage performance of different low-power and wide area technologies, i.e., long range (LoRa) backscatter, arrow band-Internet of Things (NB-IoT), and Bluetooth low energy (BLE) based BC at different frequencies of operation. To do so, we carry out a comprehensive campaign of simulations while using a sophisticated three-dimensional (3D) ray tracing (RT) tool, ITU outdoor model, and 3rd generation partnership project (3GPP) indoor hotspot model. This study also covers the energy harvesting aspects of backscatter device, and it highlights the importance of future backscatter devices with high energy harvesting efficiency. The simulation results and discussion provided in this article will be helpful in understanding the coverage aspects of practical backscatter communication system in a smart city environment.
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Bunge CA, Kallweit J, Colakoglu L, Gries T. Analysis of Fibre Cross-Coupling Mechanisms in Fibre-Optical Force Sensors. Sensors (Basel) 2021; 21:2402. [PMID: 33807169 DOI: 10.3390/s21072402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/25/2021] [Accepted: 03/26/2021] [Indexed: 11/29/2022]
Abstract
The force-enhanced light coupling between two optical fibres is investigated for the application in a pressure or force sensor, which can be arranged into arrays and integrated into textile surfaces. The optical coupling mechanisms such as the influence of the applied force, the losses at the coupling point and the angular alignment of the two fibres are studied experimentally and numerically. The results reveal that most of the losses occur at the deformation of the pump fibre. Only a small percentage of the cross-coupled light from the pump fibre is actually captured by the probe fibre. Thus, the coupling and therefore the sensor signal can be strongly increased by a proper crossing angle between the fibres, which lead to a coupling efficiency of 3%, a sensitivity improvement of more than 20 dB compared to the orthogonal alignment of the two fibres.
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Gjerdrum B, Gundersen KG, Lundmark PO, Aakre BM. Refractive Precision of Ray Tracing IOL Calculations Based on OCT Data versus Traditional IOL Calculation Formulas Based on Reflectometry in Patients with a History of Laser Vision Correction for Myopia. Clin Ophthalmol 2021; 15:845-857. [PMID: 33664562 PMCID: PMC7924114 DOI: 10.2147/opth.s298007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 01/28/2021] [Indexed: 02/06/2023] Open
Abstract
Purpose To compare the refractive predictability of ray tracing IOL calculations based on OCT data versus traditional IOL calculation formulas based on reflectometry in patients with a history of previous myopic laser vision correction (LVC). Patients and Methods This was a prospective interventional single-arm study of IOL calculations for cataract and refractive lens exchange (RLE) patients with a history of myopic LVC. Preoperative biometric data were collected using an optical low coherence reflectometry (OLCR) device (Haag-Streit Lenstar 900) and two optical coherence tomography (OCT) devices (Tomey Casia SS-1000 and Heidelberg Engineering Anterion). Traditional post LVC formulas (Barret True-K no-history and Haigis-L) with reflectometry data, and ray tracing IOL calculation software (OKULIX, Panopsis GmbH, Mainz, Germany) with OCT data were used to calculate IOL power. Follow-up examination was 2 to 3 months after surgery. The main outcome measure, refractive prediction error (RPE), was calculated as the achieved postoperative refraction minus the predicted refraction. Results We found that the best ray tracing combination (Anterion-OKULIX) resulted in an arithmetic prediction error statistically significantly lower than that achieved with the best formula calculation (Barret True-K no-history) (−0.13 D and −0.32 D, respectively, adjusted p = 0.01), while the Barret TK NH had the lowest SD. The absolute prediction error was 0.26 D and 0.35 D for Anterion-OKULIX and Barret TK NH, respectively, but this was not statistically significantly different. The Anterion-OKULIX calculation also had the highest percentage of eyes within ± 0.25, compared to both formulas and within ±0.50 and ±0.75 compared to the Haigis-L (p = 0.03). Conclusion Ray tracing calculation based on OCT data from the Anterion device can yield similar or better results than traditional post LVC formulas. Ray tracing calculations are based on individual measurements and do not rely on the ocular history of the patient and are therefore applicable for any patient, also without previous refractive surgery.
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Affiliation(s)
- Bjørn Gjerdrum
- Department of Optometry, Radiography and Lighting Design, University of South-Eastern Norway, Kongsberg, Norway.,Ifocus Eye Clinic, Haugesund, Norway
| | | | - Per Olof Lundmark
- Department of Optometry, Radiography and Lighting Design, University of South-Eastern Norway, Kongsberg, Norway
| | - Bente Monica Aakre
- Department of Optometry, Radiography and Lighting Design, University of South-Eastern Norway, Kongsberg, Norway
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Kim J, Oh KH. Evaluation of the Cross-Sectional Shape of μ-Grooves Produced in Stainless Steel 304 by Laser-Induced Etching Technique. Micromachines (Basel) 2021; 12:mi12020144. [PMID: 33573214 PMCID: PMC7911725 DOI: 10.3390/mi12020144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 01/25/2021] [Accepted: 01/28/2021] [Indexed: 12/05/2022]
Abstract
The variation in cross-sectional profile of a microgroove fabricated with focused and diverging laser irradiation is demonstrated with ray tracing. To verify the result of ray tracing, stainless-steel 304 microgrooves were manufactured utilizing the conventional lens-based and optical fiber-based laser-induced etching techniques in phosphoric acid solution. Three distinctive groove geometries, i.e., a flat surface with no groove, an intermediate stage groove, and a fully developed V-groove, were rendered for numerical analysis. For focusing mode, the first and second reflections were caused by high laser intensity and the second reflected beam could lead to variation in the groove shape such as a U-shaped groove or a V-shaped groove in accordance with etchant concentration. On the contrary, a weak laser entirely distributed at the groove sidewall could not induce a chemical reaction, leading to a V-shaped groove. The effect of process variables such as laser power (intensity) and etchant concentration on the cross-sectional profiles of a groove are closely examined through the computed simulation results.
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Pohlmann D, Pilger D, Bertelmann E, von Sonnleithner C. Corneal higher-order aberrations after cataract surgery: Manual phacoemulsification versus femtosecond-laser assisted technique. Eur J Ophthalmol 2021; 31:2955-2961. [PMID: 33499651 PMCID: PMC8606799 DOI: 10.1177/1120672121990611] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Purpose: To compare and evaluate corneal higher-order aberrations (c-HOA) between conventional manual phacoemulsification (Phaco), femtosecond laser-assisted cataract surgery (FLACS), and femtosecond laser-assisted cataract surgery with astigmatic keratotomy (FSAK). Methods: In this retrospective single center study, 53 healthy individuals with cataract (73 eyes) underwent phacoemulsification with implantation of an intraocular lens. Three groups were formed: group A, Phaco (n = 27 eyes of 21 patients); group B, FLACS (n = 25 eyes of 15 patients); group C, FSAK (n = 21 eyes of 17 patients). An iTrace aberrometer (Tracey Technologies, Houston, TX, USA) was used to perform aberrometry with a pupil scan size of 5.0 mm. We used ANOVA analysis and the paired sample t-test for statistical analysis. Results: There was no difference in total c-HOA between the groups prior to surgery (F(2,66) = 2.2, p = 0.128), but some evidence for a difference between the groups after surgery (F(2,65) = 3.87, p = 0.025). After surgery, total c-HOA increased in all groups, but the greatest increase occurred FSAK. Conclusion: Manual phacoemulsification and femtosecond laser-assisted cataract surgery seem to have less impact on corneal higher-order aberrations than the combination of femtosecond laser-assisted cataract surgery with astigmatic keratotomy.
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Affiliation(s)
- Dominika Pohlmann
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Daniel Pilger
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Eckart Bertelmann
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Christoph von Sonnleithner
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
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Adnan F, Blakaj V, Phang S, Antonsen TM, Creagh SC, Gradoni G, Tanner G. Wireless power distributions in multi-cavity systems at high frequencies. Proc Math Phys Eng Sci 2021; 477:20200228. [PMID: 33633488 PMCID: PMC7897641 DOI: 10.1098/rspa.2020.0228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 11/25/2020] [Indexed: 11/23/2022] Open
Abstract
The next generations of wireless networks will work in frequency bands ranging from sub-6 GHz up to 100 GHz. Radio signal propagation differs here in several critical aspects from the behaviour in the microwave frequencies currently used. With wavelengths in the millimetre range (mmWave), both penetration loss and free-space path loss increase, while specular reflection will dominate over diffraction as an important propagation channel. Thus, current channel model protocols used for the generation of mobile networks and based on statistical parameter distributions obtained from measurements become insufficient due to the lack of deterministic information about the surroundings of the base station and the receiver-devices. These challenges call for new modelling tools for channel modelling which work in the short-wavelength/high-frequency limit and incorporate site-specific details-both indoors and outdoors. Typical high-frequency tools used in this context-besides purely statistical approaches-are based on ray-tracing techniques. Ray-tracing can become challenging when multiple reflections dominate. In this context, mesh-based energy flow methods have become popular in recent years. In this study, we compare the two approaches both in terms of accuracy and efficiency and benchmark them against traditional power balance methods.
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Affiliation(s)
- Farasatul Adnan
- Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD, USA
| | | | - Sendy Phang
- George Green Institute for Electromagnetics Research, University of Nottingham, UK
| | - Thomas M Antonsen
- Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD, USA
| | | | - Gabriele Gradoni
- School of Mathematical Sciences, and
- George Green Institute for Electromagnetics Research, University of Nottingham, UK
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Shams R, Otero P, Aamir M, Hanif F. E2JSL: Energy Efficient Joint Time Synchronization and Localization Algorithm Using Ray Tracing Model. Sensors (Basel) 2020; 20:E7222. [PMID: 33348557 DOI: 10.3390/s20247222] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/30/2020] [Accepted: 12/10/2020] [Indexed: 11/22/2022]
Abstract
In underwater wireless sensor networks (UWSNs), localization and time synchronization are vital services that have been tackled independently. By combining localization and time synchronization, could save nodes energy and improve accuracy jointly. Therefore, it is of great significance to study joint synchronization and localization of underwater sensors with low energy consumption. In this paper, we propose the energy-efficient joint framework of localization and time synchronization, in which the stratification effect is considered by using a ray-tracing approach. Based on Snell’s law, ray tracing is applied to compensate for the variation of sound speed, this is one of the contributions of this article. Another contribution of this article is the iteration process which is used to improve the accuracy of localization and time synchronization. Simulation results show that the proposed joint approach outperforms the existing approaches in both energy efficiency and accuracy. This study also calculates Cramer-Rao lower bound to prove the convergence of the proposed technique along with the calculation of complexity of the proposed algorithm to show that the provided study takes less running time compared to the existing techniques.
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Mao K, Zhu Q, Song M, Hua B, Zhong W, Ye X. A Geometry-Based Beamforming Channel Model for UAV mmWave Communications. Sensors (Basel) 2020; 20:s20236957. [PMID: 33291413 PMCID: PMC7731107 DOI: 10.3390/s20236957] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 11/29/2020] [Accepted: 12/03/2020] [Indexed: 11/16/2022]
Abstract
Considering the three-dimensional (3D) trajectory, 3D antenna array, and 3D beamforming of unmanned aerial vehicle (UAV), a novel non-stationary millimeter wave (mmWave) geometry-based stochastic model for UAV to vehicle communication channels is proposed. Based on the analysis results of measured and ray tracing simulation data of UAV mmWave communication links, the proposed parametric channel model is constructed by a line-of-sight path, a ground specular path, and two strongest single-bounce paths. Meanwhile, a new parameter computation method is also developed, which is divided into the deterministic (or geometry-based) part and the random (or empirical) part. The simulated power delay profile and power angle profile demonstrate that the statistical properties of proposed channel model are time-variant with respect to the scattering scenarios, positions and beam direction. Moreover, the simulation results of autocorrelation functions fit well with the theoretical ones as well as the measured ones.
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Affiliation(s)
- Kai Mao
- The Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space, College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China; (K.M.); (M.S.); (B.H.); (X.Y.)
| | - Qiuming Zhu
- The Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space, College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China; (K.M.); (M.S.); (B.H.); (X.Y.)
- Correspondence:
| | - Maozhong Song
- The Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space, College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China; (K.M.); (M.S.); (B.H.); (X.Y.)
| | - Boyu Hua
- The Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space, College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China; (K.M.); (M.S.); (B.H.); (X.Y.)
| | - Weizhi Zhong
- The Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space, College of Astronautics, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China;
| | - Xijuan Ye
- The Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space, College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 211106, China; (K.M.); (M.S.); (B.H.); (X.Y.)
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Elsawy A, Gregori G, Eleiwa T, Abdel-Mottaleb M, Shousha MA. Pathological-Corneas Layer Segmentation and Thickness Measurement in OCT Images. Transl Vis Sci Technol 2020; 9:24. [PMID: 33173606 PMCID: PMC7594599 DOI: 10.1167/tvst.9.11.24] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 09/22/2020] [Indexed: 11/26/2022] Open
Abstract
Purpose The purpose of this study was to propose a new algorithm for the segmentation and thickness measurement of pathological corneas with irregular layers using a two-stage graph search and ray tracing. Methods In the first stage, a graph, with only gradient edge-cost, is used to segment the air-epithelium and endothelium-aqueous boundaries. In the second stage, a graph, with gradient, directional, and multiplier edge-cost, is used to correct segmentation. The optical coherence tomography (OCT) image is flattened using the air-epithelium boundary and a graph search is used to segment the epithelium-Bowman's and Bowman's-stroma boundaries. Then, the OCT image is flattened using the endothelium-aqueous boundary and a graph search is used to segment the Descemet's membrane. Ray tracing is used to correct the inter-boundary distances, then the thickness is measured using the shortest distance. The proposed algorithm was trained and evaluated using 190 OCT images manually segmented by trained operators. Results The mean and standard deviation of the unsigned errors of the algorithm-operator and inter-operator were 0.89 ± 1.03 and 0.77 ± 0.68 pixels in segmentation and 3.62 ± 3.98 and 2.95 ± 2.52 µm in thickness measurement. Conclusions Our proposed algorithm can produce accurate segmentation and thickness measurements compared with the manual operators. Translational Relevance Our algorithm could be potentially useful in the clinical practice.
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Affiliation(s)
- Amr Elsawy
- Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL, USA
- Electrical and Computer Engineering, University of Miami, Miami, FL, USA
| | - Giovanni Gregori
- Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Taher Eleiwa
- Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL, USA
- Ophthalmology Department, Benha Faculty of Medicine, Egypt
| | | | - Mohamed Abou Shousha
- Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL, USA
- Electrical and Computer Engineering, University of Miami, Miami, FL, USA
- Biomedical Engineering, University of Miami, Miami, FL, USA
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Rodríguez-Corbo FA, Azpilicueta L, Celaya-Echarri M, Lopez-Iturri P, Picallo I, Falcone F, Alejos AV. Deterministic 3D Ray-Launching Millimeter Wave Channel Characterization for Vehicular Communications in Urban Environments. Sensors (Basel) 2020; 20:E5284. [PMID: 32947776 PMCID: PMC7570788 DOI: 10.3390/s20185284] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/08/2020] [Accepted: 09/11/2020] [Indexed: 11/16/2022]
Abstract
The increasing demand for more sensors inside vehicles pursues the intention of making vehicles more "intelligent". In this context, the vision of fully connected and autonomous cars is becoming more tangible and will turn into a reality in the coming years. The use of these intelligent transport systems will allow the integration of efficient performance in terms of route control, fuel consumption, and traffic administration, among others. Future vehicle-to-everything (V2X) communication will require a wider bandwidth as well as lower latencies than current technologies can offer, to support high-constraint safety applications and data exhaustive information exchanges. To this end, recent investigations have proposed the adoption of the millimeter wave (mmWave) bands to achieve high throughput and low latencies. However, mmWave communications come with high constraints for implementation due to higher free-space losses, poor diffraction, poor signal penetration, among other channel impairments for these high-frequency bands. In this work, a V2X communication channel in the mmWave (28 GHz) band is analyzed by a combination of an empirical study and a deterministic simulation with an in-house 3D ray-launching algorithm. Multiple mmWave V2X links has been modeled for a complex heterogeneous urban scenario in order to capture and analyze different propagation phenomena, providing full volumetric estimation of frequency/power as well as time domain parameters. Large- and small-scale propagation parameters are obtained for a combination of different situations, taking into account the obstruction between the transceivers of vehicles of distinct sizes. These results can aid in the development of modeling techniques for the implementation of mmWave frequency bands in the vehicular context, with the capability of adapting to different scenario requirements in terms of network topology, user density, or transceiver location. The proposed methodology provides accurate wireless channel estimation within the complete volume of the scenario under analysis, considering detailed topological characteristics.
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Affiliation(s)
| | - Leyre Azpilicueta
- School of Engineering and Sciences, Tecnologico de Monterrey, Monterrey 64849, Mexico; (F.A.R.-C.); (M.C.-E.)
| | - Mikel Celaya-Echarri
- School of Engineering and Sciences, Tecnologico de Monterrey, Monterrey 64849, Mexico; (F.A.R.-C.); (M.C.-E.)
| | - Peio Lopez-Iturri
- Electrical, Electronic and Communication Engineering Department, Public University of Navarre, 31006 Pamplona, Spain; (P.L.-I.); (I.P.); (F.F.)
- Institute of Smart Cities, Public University of Navarre, 31006 Pamplona, Spain
| | - Imanol Picallo
- Electrical, Electronic and Communication Engineering Department, Public University of Navarre, 31006 Pamplona, Spain; (P.L.-I.); (I.P.); (F.F.)
- Institute of Smart Cities, Public University of Navarre, 31006 Pamplona, Spain
| | - Francisco Falcone
- Electrical, Electronic and Communication Engineering Department, Public University of Navarre, 31006 Pamplona, Spain; (P.L.-I.); (I.P.); (F.F.)
- Institute of Smart Cities, Public University of Navarre, 31006 Pamplona, Spain
| | - Ana Vazquez Alejos
- Signal and Communications Theory Department, University of Vigo, 36310 Vigo, Spain;
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Zhang X, Guo Z, Meng X, Chen J, Ji Z, Jin Z, Zhang X, Wang Y, Tai R. Design of an online spectrometer for the diagnosis of free-electron lasers. J Synchrotron Radiat 2020; 27:870-882. [PMID: 33565995 DOI: 10.1107/s1600577520006554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 05/15/2020] [Indexed: 06/12/2023]
Abstract
A self-amplified spontaneous emission free-electron laser (FEL) is under construction at the Shanghai Soft X-ray Free-Electron Facility. Therefore, it is necessary to develop a suitable diagnostic tool capable of resolving the natural emission band of each FEL pulse. Thus, an online spectrometer with a plane mirror and plane variable-line-spacing grating at grazing incidence to monitor each single FEL pulse during the propagation of FEL radiation has been designed and is presented in this work. The method of ray tracing is used for monitoring incident radiation in order to understand spectral characteristics, and SHADOW, an X-ray optics simulation tool, and SRW, an X-ray optics wavefront tool, are applied to study the resolving power and focusing properties of the grating. The designed resolving power is ∼3 × 104 at 620 eV. Meanwhile, the effect of the actual slope error of mirrors on the ray-tracing results is also discussed. In order to provide further optimization for the choice of grating, a comparison of resolving powers between 2000 lines mm-1 and 3000 lines mm-1 gratings at different energies is analyzed in detail and radiation damage of mirrors as well as parameters such as the first-order diffraction angle β, the exit-arm length r2, and the tilt angle θ between the focal plane and the diffraction arm are studied and optimized. This work has provided comprehensive designing methods and detailed data for the design of diagnostic spectrometers in soft X-ray FELs and will be favorable to the design of other similar instruments.
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Affiliation(s)
- Ximing Zhang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 2019 Jialuo Highway, Jiading District, Shanghai 201800, People's Republic of China
| | - Zhi Guo
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 2019 Jialuo Highway, Jiading District, Shanghai 201800, People's Republic of China
| | - Xiangyu Meng
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 2019 Jialuo Highway, Jiading District, Shanghai 201800, People's Republic of China
| | - Jiahua Chen
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 2019 Jialuo Highway, Jiading District, Shanghai 201800, People's Republic of China
| | - Zhan Ji
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 2019 Jialuo Highway, Jiading District, Shanghai 201800, People's Republic of China
| | - Zuanming Jin
- Shanghai University, 99 Shangda Road, Baoshan District, Shanghai 200444, People's Republic of China
| | - Xiangzhi Zhang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 2019 Jialuo Highway, Jiading District, Shanghai 201800, People's Republic of China
| | - Yong Wang
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 2019 Jialuo Highway, Jiading District, Shanghai 201800, People's Republic of China
| | - Renzhong Tai
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 2019 Jialuo Highway, Jiading District, Shanghai 201800, People's Republic of China
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Abstract
Investigators, scientists, and physicians continue to develop new methods of intraocular lens (IOL) calculation to improve the refractive accuracy after cataract surgery. To gain more accurate prediction of IOL power, vergence lens formulas have incorporated additional biometric variables, such as anterior chamber depth, lens thickness, white-to-white measurement, and even age in some algorithms. Newer formulas diverge from their classic regression and vergence-based predecessors and increasingly utilize techniques such as exact ray-tracing data, more modern regression models, and artificial intelligence. This review provides an update on recent literature comparing the commonly used third- and fourth-generation IOL formulas with newer generation formulas. Refractive outcomes with newer formulas are increasingly more and more accurate, so it is important for ophthalmologists to be aware of the various options for choosing IOL power. Historically, refractive outcomes have been especially unpredictable in patients with unusual biometry, corneal ectasia, a history of refractive surgery, and in pediatric patients. Refractive outcomes in these patient populations are improving. Improved biometry technology is also allowing for improved refractive outcomes and surgery planning convenience with the availability of newer formulas on various biometry platforms. It is crucial for surgeons to understand and utilize the most accurate formulas for their patients to provide the highest quality of care.
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Affiliation(s)
- Tina Xia
- John F Hardesty MD Department of Ophthalmology and Visual Sciences, Washington University in St. Louis School of Medicine, St. Louis MO
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Yang J, Liu G, Liu HY, Nie X, Yang ZY, Han J, Zhang S, Liang ZW. Influence of CyberKnife Prescription Isodose Line on the Discrepancy of Dose Results Calculated by the Ray Tracing and Monte Carlo Algorithms for Head and Lung Plans: A Phantom Study. Curr Med Sci 2020; 40:301-306. [PMID: 32337689 DOI: 10.1007/s11596-020-2177-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 03/24/2020] [Indexed: 11/29/2022]
Abstract
Incorporation of the Monte Carlo (MC) algorithm in optimizing CyberKnife (CK) plans is cumbersome, and early models unconfgured MC calculations, therefore, this study investigated algorithm-based dose calculation discrepancies by selecting different prescription isodose lines (PIDLs) in head and lung CK plans. CK plans were based on anthropomorphic phantoms. Four shells were set at 2-60 mm from the target, and the constraint doses were adjusted according to the design strategy. After optimization, 30%-90% PIDL plans were generated by ray tracing (RT). In the evaluation module, CK plans were recalculated using the MC algorithm. Therefore, the dosimetric parameters of different PIDL plans based on the RT and MC algorithms were obtained and analyzed. The discrepancies (mean±SD) were 3.72%±0.31%, 3.40%±0.11%, 3.47%±0.32%, 0.17%±0.11%, 0.64%±3.60%, 7.73%±1.60%, 14.62%±3.21% and 10.10%±1.57% for D1%, D(mean), D98% and coverage of the PTV, DGI, V5, V3 and V1 in the head plans and -6.32%±1.15%, -13.46%±0.98%, -20.63%±2.25%, -34.78%±25.03%, 122.48%±175.60%, -12.92%±5.41%, 3.19%±4.67% and 7.13%±1.56% in the lung plans, respectively. The following parameters were signifcantly correlated with PIDL: dD98% at the 0.05 level and dDGI, dV5 and dV3 at the 0.01 level for the head plans; dD98% at the 0.05 level and dD1%, dD(mean), dCoverage, dDGI, dV5 and dV3 at the 0.01 level for the lung plans. RT may be used to calculate the dose in CK head plans, but when the dose of organs at risk is close to the limit, it is necessary to refer to the MC results or to further optimize the CK plan to reduce the dose. For lung plans, the MC algorithm is recommended. For early models without the MC algorithm, a lower PIDL plan is recommended; otherwise, a large PIDL plan risks serious underdosage in the target area.
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Affiliation(s)
- Jing Yang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430023, China
| | - Gang Liu
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430023, China
| | - Hong-Yuan Liu
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430023, China
| | - Xin Nie
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430023, China
| | - Zhi-Yong Yang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430023, China
| | - Jun Han
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430023, China
| | - Sheng Zhang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430023, China
| | - Zhi-Wen Liang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430023, China.
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Jiang C, Li D, Xu F, Li Y, Liu C, Ta D. Numerical Evaluation of the Influence of Skull Heterogeneity on Transcranial Ultrasonic Focusing. Front Neurosci 2020; 14:317. [PMID: 32351351 PMCID: PMC7174677 DOI: 10.3389/fnins.2020.00317] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Accepted: 03/17/2020] [Indexed: 11/13/2022] Open
Abstract
In transcranial penetration, ultrasound undergoes refraction, diffraction, multi-reflection, and mode conversion. These factors lead to phase aberration and waveform distortion, which impede the realization of transcranial ultrasonic imaging and therapy. Ray tracing has been used to correct the phase aberration and is computationally more efficient than traditional full-wave simulation. However, when ray tracing has been used for transcranial investigation, it has generally been on the premise that the skull medium is homogeneous. To find suitable homogeneity that balances computational speed and accuracy, the present work investigates how the focus deviates after phase-aberration compensation with ray tracing using time-reversal theory. The waveforms are synthetized with ray tracing for phase aberration, by which the properties of the skull bone are simplified for refraction calculation as those of either (i) the cortical bone or (ii) the mean of the entire skull bone, and the focusing accuracy is evaluated for each hypothesis. The propagation of ultrasound for transcranial focusing is simulated with the elastic model using the k-space pseudospectral method. Unlike the fluid model, the elastic model does not omit shear waves in the skull bones, and the influence of that omission is investigated, with the fluid model resulting in a focal deflection of 0.5 mm. The focusing deviations are huge when the properties of the skull bone are idealized with ray tracing as those of the mean of the entire skull bone. The focusing accuracy improves when the properties of the skull bone are idealized as those of the cortical bone. The results reveal minimal deviation (8.6, 3.9, and 3.2% in the three Cartesian coordinates) in the focal region and suggest that transcranial focusing deflections are caused mostly by ultrasonic refraction on the surface of the skull bone. A heterogeneous skull bone causes wave bending but minimal focusing deflection. The proposed simplification of a homogeneous skull bone is more accurate for transcranial ultrasonic path estimation and offers promising applications in transcranial ultrasonic focusing and imaging.
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Affiliation(s)
- Chen Jiang
- Department of Electronic Engineering, Fudan University, Shanghai, China
| | - Dan Li
- Department of Electronic Engineering, Fudan University, Shanghai, China
| | - Feng Xu
- Department of Electronic Engineering, Fudan University, Shanghai, China
| | - Ying Li
- Department of Electronic Engineering, Fudan University, Shanghai, China
| | - Chengcheng Liu
- Institute of Acoustics, Tongji University, Shanghai, China
| | - Dean Ta
- Department of Electronic Engineering, Fudan University, Shanghai, China.,State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai, China.,Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention (MICCAI) of Shanghai, Shanghai, China
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42
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Wang Y, Li X. Elbow Damage Identification Technique Based on Sparse Inversion Image Reconstruction. Materials (Basel) 2020; 13:ma13071786. [PMID: 32290126 PMCID: PMC7179036 DOI: 10.3390/ma13071786] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/13/2020] [Accepted: 04/08/2020] [Indexed: 11/16/2022]
Abstract
Continuous monitoring for defects in oil and gas pipelines is important for leakage prevention. This paper proposes a new kind of pipe elbow damage identification technique, which consists of three processes. First, piezoelectric sensors evenly arranged along the circumference of the pipeline in the turn generated ultrasonic guided wave signals in the elbow. Then, the wavefront flight time at each grid node in the known sound field were computed using the fast-marching algorithm. Finally, an elbow wall thickness map reconstruction technique based on the sparse inversion method was proposed to identify elbow defects. Compared with the traditional elbow defect identification technology, this technology can not only detect the existence of the defect but also accurately locate the defect position.
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43
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Oh R, Song TL, Choi JW. Batch Processing through Particle Swarm Optimization for Target Motion Analysis with Bottom Bounce Underwater Acoustic Signals. Sensors (Basel) 2020; 20:s20041234. [PMID: 32102443 PMCID: PMC7071033 DOI: 10.3390/s20041234] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 02/19/2020] [Accepted: 02/21/2020] [Indexed: 11/29/2022]
Abstract
A target angular information in 3-dimensional space consists of an elevation angle and azimuth angle. Acoustic signals propagating along multiple paths in underwater environments usually have different elevation angles. Target motion analysis (TMA) uses the underwater acoustic signals received by a passive horizontal line array to track an underwater target. The target angle measured by the horizontal line array is, in fact, a conical angle that indicates the direction of the signal arriving at the line array sonar system. Accordingly, bottom bounce paths produce inaccurate target locations if they are interpreted as azimuth angles in the horizontal plane, as is commonly assumed in existing TMA technologies. Therefore, it is necessary to consider the effect of the conical angle on bearings-only TMA (BO-TMA). In this paper, a target conical angle causing angular ambiguity will be simulated using a ray tracing method in an underwater environment. A BO-TMA method using particle swarm optimization (PSO) is proposed for batch processing to solve the angular ambiguity problem.
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Affiliation(s)
- Raegeun Oh
- Department of Marine Science & Convergence Engineering, Hanyang University ERICA, Ansan 15588, Korea;
| | - Taek Lyul Song
- Department of Electronic Systems Engineering, Hanyang University ERICA, Ansan 15588, Korea
- Correspondence: (T.L.S.); (J.W.C.); Tel.: +82-31-400-4156 (T.L.S.); +82-31-400-5531 (J.W.C.)
| | - Jee Woong Choi
- Department of Marine Science & Convergence Engineering, Hanyang University ERICA, Ansan 15588, Korea;
- Correspondence: (T.L.S.); (J.W.C.); Tel.: +82-31-400-4156 (T.L.S.); +82-31-400-5531 (J.W.C.)
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44
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Siebeneicher S, Waag F, Escobar Castillo M, Shvartsman VV, Lupascu DC, Gökce B. Laser Fragmentation Synthesis of Colloidal Bismuth Ferrite Particles. Nanomaterials (Basel) 2020; 10:E359. [PMID: 32092944 DOI: 10.3390/nano10020359] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/07/2020] [Accepted: 02/13/2020] [Indexed: 12/04/2022]
Abstract
Laser fragmentation of colloidal submicron-sized bismuth ferrite particles was performed by irradiating a liquid jet to synthesize bismuth ferrite nanoparticles. This treatment achieved a size reduction from 450 nm to below 10 nm. A circular and an elliptical fluid jet were compared to control the energy distribution within the fluid jet and thereby the product size distribution and educt decomposition. The resulting colloids were analysed via UV-VIS, XRD and TEM. All methods were used to gain information on size distribution, material morphology and composition. It was found that using an elliptical liquid jet during the laser fragmentation leads to a slightly smaller and narrower size distribution of the resulting product compared to the circular jet.
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45
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Koutitas G, Kumar Siddaraju V, Metsis V. In Situ Wireless Channel Visualization Using Augmented Reality and Ray Tracing. Sensors (Basel) 2020; 20:E690. [PMID: 32012704 DOI: 10.3390/s20030690] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 01/20/2020] [Accepted: 01/21/2020] [Indexed: 11/17/2022]
Abstract
This article presents a novel methodology for predicting wireless signal propagation using ray-tracing algorithms, and visualizing signal variations in situ by leveraging Augmented Reality (AR) tools. The proposed system performs a special type of spatial mapping, capable of converting a scanned indoor environment to a vector facet model. A ray-tracing algorithm uses the facet model for wireless signal predictions. Finally, an AR application overlays the signal strength predictions on the physical space in the form of holograms. Although some indoor reconstruction models have already been developed, this paper proposes an image to a facet algorithm for indoor reconstruction and compares its performance with existing AR algorithms, such as spatial understanding that are modified to create the required facet models. In addition, the paper orchestrates AR and ray-tracing techniques to provide an in situ network visualization interface. It is shown that the accuracy of the derived facet models is acceptable, and the overall signal predictions are not significantly affected by any potential inaccuracies of the indoor reconstruction. With the expected increase of densely deployed indoor 5G networks, it is believed that these types of AR applications for network visualization will play a key role in the successful planning of 5G networks.
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46
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Fevola G, Bergbäck Knudsen E, Ramos T, Carbone D, Wenzel Andreasen J. A Monte Carlo ray-tracing simulation of coherent X-ray diffractive imaging. J Synchrotron Radiat 2020; 27:134-145. [PMID: 31868746 DOI: 10.1107/s1600577519014425] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 10/22/2019] [Indexed: 05/28/2023]
Abstract
Coherent diffractive imaging (CDI) experiments are adequately simulated assuming the thin sample approximation and using a Fresnel or Fraunhofer wavefront propagator to obtain the diffraction pattern. Although this method is used in wave-based or hybrid X-ray simulators, here the applicability and effectiveness of an alternative approach that is based solely on ray tracing of Huygens wavelets are investigated. It is shown that diffraction fringes of a grating-like source are accurately predicted and that diffraction patterns of a ptychography dataset from an experiment with realistic parameters can be sampled well enough to be retrieved by a standard phase-retrieval algorithm. Potentials and limits of this approach are highlighted. It is suggested that it could be applied to study imperfect or non-standard CDI configurations lacking a satisfactory theoretical formulation. The considerable computational effort required by this method is justified by the great flexibility provided for easy simulation of a large-parameter space.
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Affiliation(s)
- Giovanni Fevola
- Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, Roskilde 4000, Denmark
| | - Erik Bergbäck Knudsen
- Department of Physics, Technical University of Denmark, Fysikvej 311, Kgs Lyngby 2800, Denmark
| | - Tiago Ramos
- Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, Roskilde 4000, Denmark
| | - Dina Carbone
- MAX IV Laboratory, Lund University, 22484 Lund, Sweden
| | - Jens Wenzel Andreasen
- Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, Roskilde 4000, Denmark
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Li Z, Li B. Towards an extremely high resolution broad-band flat-field spectrometer in the `water window'. J Synchrotron Radiat 2019; 26:1058-1068. [PMID: 31274428 PMCID: PMC6613118 DOI: 10.1107/s1600577519004648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 04/05/2019] [Indexed: 06/09/2023]
Abstract
The optical design of a novel spectrometer is presented, combining a cylindrically convex pre-mirror with a cylindrically concave varied-line-spacing grating (both in the meridional) to deliver a resolving power of 100000-200000 in the `water window' (2-5 nm). Most remarkably, the extremely high spectral resolution is achieved for an effective meridional source size of 50 µm (r.m.s.); this property could potentially be applied to diagnose SASE-FEL and well resolve individual single spikes in its radiation spectrum. The overall optical aberrations of the system are well analysed and compensated, providing an excellent flat-field at the detector domain throughout the whole spectral range. Also, a machine-learning scheme - SVM - is introduced to explore and reconstruct the optimal system with high efficiency.
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Affiliation(s)
- Zhuo Li
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Jiading District, Shanghai 201800, People’s Republic of China
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Zhangjiang Laboratory, Chinese Academy of Sciences, Pudong District, Shanghai 201204, People’s Republic of China
| | - Bin Li
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Jiading District, Shanghai 201800, People’s Republic of China
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Zhangjiang Laboratory, Chinese Academy of Sciences, Pudong District, Shanghai 201204, People’s Republic of China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People’s Republic of China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, People’s Republic of China
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Abadi E, Harrawood B, Sharma S, Kapadia A, Segars WP, Samei E. DukeSim: A Realistic, Rapid, and Scanner-Specific Simulation Framework in Computed Tomography. IEEE Trans Med Imaging 2019; 38:1457-1465. [PMID: 30561344 PMCID: PMC6598436 DOI: 10.1109/tmi.2018.2886530] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The purpose of this study was to develop a CT simulation platform that is: 1) compatible with voxel-based computational phantoms; 2) capable of modeling the geometry and physics of commercial CT scanners; and 3) computationally efficient. Such a simulation platform is designed to enable the virtual evaluation and optimization of CT protocols and parameters for achieving a targeted image quality while reducing radiation dose. Given a voxelized computational phantom and a parameter file describing the desired scanner and protocol, the developed platform DukeSim calculates projection images using a combination of ray-tracing and Monte Carlo techniques. DukeSim includes detailed models for the detector quantum efficiency, quantum and electronic noise, detector crosstalk, subsampling of the detector and focal spot areas, focal spot wobbling, and the bowtie filter. DukeSim was accelerated using GPU computing. The platform was validated using physical and computational versions of a phantom (Mercury phantom). Clinical and simulated CT scans of the phantom were acquired at multiple dose levels using a commercial CT scanner (Somatom Definition Flash; Siemens Healthcare). The real and simulated images were compared in terms of image contrast, noise magnitude, noise texture, and spatial resolution. The relative error between the clinical and simulated images was less than 1.4%, 0.5%, 2.6%, and 3%, for image contrast, noise magnitude, noise texture, and spatial resolution, respectively, demonstrating the high realism of DukeSim. The runtime, dependent on the imaging task and the hardware, was approximately 2-3 minutes per rotation in our study using a computer with 4 GPUs. DukeSim, when combined with realistic human phantoms, provides the necessary toolset with which to perform large-scale and realistic virtual clinical trials in a patient and scanner-specific manner.
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Egidi A, Balsamo A, Pisani M. High-Index Glass Ball Retroreflectors for Measuring Lateral Positions. Sensors (Basel) 2019; 19:s19051082. [PMID: 30832424 PMCID: PMC6427531 DOI: 10.3390/s19051082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/17/2019] [Accepted: 02/27/2019] [Indexed: 11/16/2022]
Abstract
This paper is concerned with backscattered luminous signals, coming from a particular class of dielectric spheres illuminated by a coherent source. The purpose is to measure the lateral position of the sphere serving as an optical target, to achieve an overall contactless sensor of lateral position in space. Traditional approaches and theories such as ray-tracing and Mie scattering—as implemented in dedicated software—are applied to investigate their fitness for purpose in this application. No previous literature was found dealing with this specific case. Unfortunately, our observations did not match the theories’ predictions to an acceptable degree, and these approaches proved to be unsatisfactory. The rest of the paper focusses then on the development and comparison of suitable algorithms to compute the image coordinates of a representative point, which was in fact the true motivation of this work. Two original algorithms are proposed and discussed. Their robustness and repeatability are benchmarked under noisy conditions and at different distances from the target, with simulated as well as real images. Both resulted capable of sub-pixel accuracy.
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Affiliation(s)
- Andrea Egidi
- INRiM-National Institute of Research in Metrology, Division of Applied Metrology and Engineering, Torino 10135, Italy.
| | - Alessandro Balsamo
- INRiM-National Institute of Research in Metrology, Division of Applied Metrology and Engineering, Torino 10135, Italy.
| | - Marco Pisani
- INRiM-National Institute of Research in Metrology, Division of Applied Metrology and Engineering, Torino 10135, Italy.
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50
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Wang F, Wald I, Wu Q, Usher W, Johnson CR. CPU Isosurface Ray Tracing of Adaptive Mesh Refinement Data. IEEE Trans Vis Comput Graph 2018; 25:10.1109/TVCG.2018.2864850. [PMID: 30334795 PMCID: PMC6898768 DOI: 10.1109/tvcg.2018.2864850] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Adaptive mesh refinement (AMR) is a key technology for large-scale simulations that allows for adaptively changing the simulation mesh resolution, resulting in significant computational and storage savings. However, visualizing such AMR data poses a significant challenge due to the difficulties introduced by the hierarchical representation when reconstructing continuous field values. In this paper, we detail a comprehensive solution for interactive isosurface rendering of block-structured AMR data. We contribute a novel reconstruction strategy-the octant method-which is continuous, adaptive and simple to implement. Furthermore, we present a generally applicable hybrid implicit isosurface ray-tracing method, which provides better rendering quality and performance than the built-in sampling-based approach in OSPRay. Finally, we integrate our octant method and hybrid isosurface geometry into OSPRay as a module, providing the ability to create high-quality interactive visualizations combining volume and isosurface representations of BS-AMR data. We evaluate the rendering performance, memory consumption and quality of our method on two gigascale block-structured AMR datasets.
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